Here is patch with a subdued message to see Help when IDLE Dark is selected.  It goes away when something else is selected. I tried no emphasis, colored background, relief, and the dull red text in the patch.  I tested, but I want to retest systematically when fresh.  Test on *nix would good, though I do not think anything is system specific.

Under some conditions, entry 'new = ' is being put in user config-main.cfg [Theme] section. It seems harmless but I hope to track it down, while retesting, before committing.  It might just be something I did in my installed idlelib, but I'd like to know.